This disclosure relates to wellsite operations. In particular, this disclosure relates to downhole measurement, stimulation and/or fracturing techniques.
Identifying the composition of a geological formation can provide information about the likely presence or absence of hydrocarbons in a subsurface geological formation. As such, many downhole tools have been developed that aim to analyze the geological formation from within a wellbore. Electromagnetic logging tools are one type of downhole tool that may be used to measure properties of the geological formation.
Transverse isotropy, or uniaxial anisotropy, is generally encountered in subsurface formations because of thinly-layered structures or intrinsic anisotropy of sedimentary rocks. When fractures or faults are developed in formations, the resistivity of the formations can be different in all three orthogonal directions, leading to triaxial anisotropy in the formations (also called bi-axial anisotropy in optical terms in the literature).
The triaxial anisotropy can be found in formations generally considered transversely isotropic, such as shales and laminated sands. It can also happen in fairly isotropic formations, such as carbonates if the density, width, length, opening, and orientation, etc., of fractures change from place to place in the fractured zone. Examples of tri-axial related techniques are provided in U.S. Pat. Nos. 7,386,430, 6,977,021, 6,924,646, 6798708, 2014/0305692, 2013/0335092, 2012/0065889, and 2010/0256964, the entire contents of which are hereby incorporated by reference herein.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present techniques, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as an admission of any kind.